Day 4: Chimney Fire Safety Week – Terminals!

A chimney terminal is the bit right at the top – sometimes known as a cage, cap, cowl, birdguard or ‘chimney thingy’! There are a number of uses:

  • Keeping out birds (Jackdaws) who nest in the flue and vermin such as squirrels
  • Keeping out rain
  • Combating down draught problems

Some homes may not need anything on the chimney – sometimes a chimney pot is sufficient – indeed occasionally even a pot isn’t needed! But anyone with a woodburner, multi-fuel stove, AGA or similar appliance are advised to have a cowl of some type, if only to prevent water ingress – water will rust away the metal box beneath and can mix with the soot to create a corrosive substance in the flue.

Having the correct terminal is important and we frequently see the wrong type fitted and/or fitted incorrectly – perhaps the wrong advice has been given or simply the customer has changed how they use the flue and not considered the other end of their chimney.

Simply put, whatever is fitted to a ‘live’ chimney (one in use) should be installed so that it:

  • can be swept into without dislodging it – ensuring that the flue is clear all the way to the top
  • allows the safe removal of gases caused by combustion to pass out of the flue
  • prevents condensation build up in the flue of a disused chimney

Flue vent: AKA pepperpot top / Clay cowl / Elephants Foot

 

If you use any appliance or open fire you should NOT have this type of terminal on your chimney.  They are dangerous as fumes are prevented from escaping quickly enough – they are not designed to be used with a live flue and could result in the build-up of highly poisonous carbon monoxide.  

 

 

If you have a problem with birds, rain or vermin entry into your chimney – there’s a cowl for that. The silver one on the right can also aid with a down draught (in certain circumstances).  There are also a variety of chimney pots and cowls for lined chimneys.

 

 

 

This terminal is a no-no for any live chimney. It doesn’t prevent any birds entering – in fact it’s a lovely shelter for the birds – and the cowl will impede the outflow of fumes. In addition, the design of many clay terminals, which are not intended to get hot, means that the tops can crack and be dislodged in windy conditions or when the chimney is swept.  This can damage roof tiles/slates…or worse!

BONNET COWL

 

 

 

If you need any ‘terminal’ advice contact your local professional qualified chimney sweep or experienced chimney expert builder or woodburner supplier. Whilst a roofer will be able to install a unit they may not have the necessary skills to advise what should be fitted for safety.

Be safe!

Louise Harris

Franchise Director

Wilkins Chimney Sweep

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